Inhibition of cell adhesion for reducing cancer cell metastases

ABSTRACT

Lipids obtained from blackcurrant seed are used for preventing proliferation and dissemination of cancerous metastases in patients.

This invention relates to the use of a blackcurrant lipid in a dieteticor pharmaceutical composition to prevent the adhesion phenomenaresponsible for certain thrombo-embolic, inflammatory and cancerousdiseases.

BACKGROUND OF THE INVENTION

It is known that polyunsaturated fatty acids of the ω3 and ω6 serieshave very important structural and functional roles. Polyunsaturatedfatty acids can be defined by the number of carbon atoms, the number ofdouble bonds and the number indicating the position of the first doublebond counting from the methyl group which determines their metabolicfamily designated ω. Thus, in this nomenclature, dihomogammalinolenicacid (DHLA) is C20:3ω6, eicosapentaenoic acid (EPA) is C20:5ω3 andarachidonic acid (AA) is C20:4ω6. The fatty acids linoleic acid (LA,C18:2ω6) and alphalinolenic acid (ALA, C18:3ω3) are the essentialprecursors of the other acids of the two families which are notsynthesized by mammalians. No metabolism allows passage from one familyto the other. The conversion of LA or ALA into the respective uppermembers of the two families is obtained by successive desaturation andelongation with relatively low yields.

The prostaglandins form a family of substances which show numerousbiological effects. DHLA, AA and EPA are transformed under the effect ofcyclo-oxygenase into prostaglandins of the 1(PG1), 2(PG2) and 3(PG3)series, respectively. The PGS of series 1, 2 and 3 respectively comprise1, 2 and 3 double bonds in their basic structure of C₂₀ fatty acidsincluding a cyclopentene group. Among other properties, the PG1S(emanating from DHLA) are capable of inhibiting the aggregation of bloodplatelets. By contrast, the eicosanoides of series 2 (emanating fromAA), for example PG2, thromboxanes, for example PxA2, promote plateletaggregation. The eicosanoides of series 3 (emanating from EPA) have asimilar role to the eicosanoides of series 1.

It is assumed that the effectiveness of EPA and DHLA in the preventionof cardiovascular diseases of the thrombo-embolic type is based on thefavourable effects of the PG3S and PG1S compared with the effects of thePG2S.

In addition, the enzyme system lipoxygenase leads to hydroxylated fattyacids and to leucotrienes from the precursors AA and EPA. Recent studiessuggest, in particular, that the compounds 13-hydroxyoctadecatrienoicacid (13-HODE), produced by the endothelial cells of the blood vessels,and 12-hydroxyeicosatetraenoic acid (12-HETE), produced by the plateletsvia the lipoxygenase, play an important part in the mediation ofinter-cell adhesion and hence, in the pathogenesis of thromboses,inflammatory diseases and the dissemination of cancerous metastases. Insimple terms, adhesion would be influenced by the regulators 12-HETE and13-HODE positively by AA, the precursor of 12-HETE, and negatively byLA, leading to 13-HODE. In addition, DHLA is not susceptible to thelipoxygenase.

It has been proposed, for example in published French patent applicationno. 2 553 662, to add to a pharmaceutical composition or to a foodproduct a mixture of a first fatty acid selected from EPA ordocosahexaenoic acid (DHA) on the one hand and a second fatty acidselected from DHLA, cis-linoleic acid, gammalinolenic acid (GLA) on theother hand with the object of preventing cardiovascular diseases. Inthis patent application, the fatty acids in question must have beenseparately isolated from natural fats by iodination followed bysaponification, solvent extraction of the fatty acids, methylationthereof, separation of the methylesters by chromatography and, finally,deiodination. EPA, for example, is obtained in this way from cod liveroil. The production of such a composition is particularly complicated.

In addition, EPA is particularly unstable. Finally, there are somepeople who cannot bear any recollection of bad tastes coming from fishoil, even in deodorized or encapsulated form.

SUMMARY OF THE INVENTION

It has now been found that, by using a lipid of the blackcurrant, it ispossible to provide EPA conjointly with DHLA while depressing thebioavailability of AA without any of the disadvantages associated withingestion of fish oil, for example an increase in bleeding time whichcan cause haemorrhages. Very interesting effects are obtained in thisway in regard to prevention of the adhesion and aggregation ofplatelets, thromboses and the dissemination of cancerous metastases.

Accordingly, the present invention relates to the use of a blackcurrantlipid for the preparation of a dietetic or pharmaceutical compositioncapable of promoting the bioavailability of dihomogammalinolenic acidand eicosapentaenoic acid over the bioavailability of arachidonic acid.

The uses of the lipids of blackcurrant disclosed herein include usingthe ipis for prevention of diseases of inflammatory origin, forprevention of adhesion of platelets, for prevention of plateletaggregation, for prevention of thrombosis, for prevention ofproliferation and dissemination of cancerous metastases and forinhibiting adhesion of immune cells.

In the context of the invention, blackcurrant lipid is understood to be

blackcurrant (Ribes nigrum) seed oil obtained by extraction fromblackcurrant residues and refining, for example as indicated in Europeanpatent 92 085 or European patent 137 862,

a mixture of fatty acids emanating from the hydrolysis or fractionationof blackcurrant seed oil obtained for example in accordance withEuropean patent 178 442 or European patent application 271 747,

a pharmaceutically acceptable salt of the above-mentioned fatty acids,

an oil obtained by reesterification of such a mixture of fatty acidswith glycerol,

a mixture of the above-mentioned lipids.

The blackcurrant lipid may advantageously be protected against oxidationby a fat-soluble antioxidant, for example ascorbyl palmitate,tocopherols, ascorbic acid in the presence of lecithin or a mixture ofsuch antioxidants.

The dietetic compositions may be made up in the form of emulsions, forexample sauces, mayonnaises or margarines.

The pharmaceutical compositions may be made up in various forms adaptedto the method of administration, for example oral, enteral, rectal orparenteral. For example, they may be made up in the form of capsules,gelatin-coated pills, suppositories or syrups. In the case of enteral orparenteral administration, the compositions are formulated as apyrogenicand sterile, physically and chemically stable solutions or emulsions.

The dose administered depends on the type and seriousness of the diseaseto be treated. Effective quantities may be from 1 to 25 g blackcurrantlipid and preferably from 2 to 5 g blackcurrant oil per day in a singledose or preferably in 2 to 3 separate doses.

EXAMPLES

The invention is illustrated by the following Examples in which partsand percentages are by weight, unless otherwise stated.

EXAMPLE 1 Incorporation of DHLA and EPA in the tissues

Many pharmacological studies on the ability to modulate the fatty acidsof the tissues by diet have used primarily rats as the experimentalmodel. It is known that, in rats or mice, the ingestion of GLA leads toan increase in the incorporation of GLA in triglycerides or of DHLA inthe total lipids, but not the phospholipids. By contrast, in humanbeings, rabbits and guinea pigs, the ingestion of GLA leads to theincorporation of DHLA in the triglycerides and the phospholipids of theblood, in the membrane of the red corpuscles and in all the lipids. Forthis reason, guinea pigs have been preferred to rats because, being muchcloser to man in regard to desaturase activity, they reflect better thesituation prevailing in human beings. Also, the liver was chosen as thetissue because it represents the major site of fatty acid conversions.

1.1 Experimental Conditions

3 Groups of 7 male guinea pigs each weighing approximately 300 g areformed and are placed in cages of MACROLON. The groups are fed onsemi-synthetic diets respectively containing blackcurrant seed oil(HPC), I, walnut oil (WO), II, or lard (L), III, "ad libitum" for 40days. The WO is selected for comparison with the HPC because it does notcontain the acids GLA and stearidonic acid (SA), but more LA, so thatthe total quantities of ω6 and ω3 and their ratios are comparable in thetwo oils.

All the animals have free access to water containing 250 mg/1 ascorbicacid. After one night without food, the animals are anaesthetized, theirlivers are removed and rapidly frozen, finely ground and then stored at-80° C. lipids ingested are shown in Tables 1 and 2 below.

                  TABLE 1                                                         ______________________________________                                        Composition of the base diet:                                                 Ingredient       %                                                            ______________________________________                                        Casein           30                                                           Starch           20                                                           Sucrose          10                                                           Glucose          3.8                                                          Cellulose        15                                                           Mineral salts    6                                                            Vitamins         2.2                                                          Potassium acetate                                                                              2.5                                                          Magnesium oxide  0.5                                                          Lipid            10                                                           ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        Fatty acid composition of the lipids of the diets                             (in mol-%)                                                                    Fatty acids   HPC        WO      L                                            ______________________________________                                        C14:0         --         --      2.7                                          C16:0         7.4        8.6     32.4                                         C16:1         --         --      3.4                                          C17:0         --         --      0.5                                          C17:1         --         --      0.3                                          C18:0         0.8        1.9     14.2                                         C18:1ω9 10.4       20.8    36.7                                         C18:2ω6 48.1       57.7    8.4                                          C18:3ω6 17.1       --      --                                           C18:3ω3 12.7       11.0    0.7                                          C18:4ω3 2.6        --      --                                           C20:1ω9 0.6        --      0.7                                          C20:2ω6 0.3        --      --                                           Total ω6's                                                                            65.5       57.7    8.4                                          Total ω3's                                                                            15.3       11.0    0.7                                          ω6:ω3 ratio                                                                     4.3        5.2     12.0                                         Unsaturation index.sup.1                                                                    207.6      169.2   59.8                                         ______________________________________                                         Legend                                                                        .sup.1 The unsaturation index is the sum of the products a × b wher     a is the molar percentage of each unsaturated fatty acid and b is the         number of double bonds of that particular fatty acid.                    

1.2 Analysis of the Fatty Acids

1.2.1

The samples are prepared by homogenizing 1 g frozen hepatic tissue in 20ml of a solvent mixture of chloroform and methanol (ratio 2:1 by volume)and the total lipids (TLS) are extracted after separation of theprecipitated solids by filtration, followed by elimination of thesolvents.

1.2.2

The TLS are separated into neutral lipids (NLS) and polar lipids (PLS)by passage through a column of silica gel. The non-acidic and acidicfractions are separated from the PLS in ion exchange columns filled withdiethylaminoethyl sepharose gel. The fraction of acidic polar lipids isthen freed from salts by passage through a column of silica gel.

1.2.3

The NLS are separated into their various components by high-performancethin-layer chromatography (HPTLC) using glass plates coated with silicicacid. The plates are developed with a solvent mixture of petroleumether, diethyl ether and acetic acid in a ratio by volume of 85:15:0.5,dried in air, sprayed with a 0.005% solution of primuline in acetone(weight/volume) and the bands corresponding to the various lipids arevisualized with UV rays. The esters of cholesterol (CES) triglycerides(TGS) and free fatty acids (FFAS) were identified by comparison withstandard products and collected in glass tubes closed with Teflon-coatedstoppers.

1.2.4

The PLS are separated into their various components by HPTLC on silicagel plates impregnated with a 2% (weight/volume) solution of boric acidin absolute methanol. The plates are developed with a solvent mixture ofchloroform, methanol, triethylamine and water in a ratio by volume of30:25:34:8. The acidic phospholipids phosphatidyl serine (PS),phosphatidyl inositol (PI), cardiolipine (CL), and the non-acidicphospholipids phosphatidyl ethanolamine (PE) and phosphatidyl choline(PC) were visualized in the same way as the neutral lipids, identifiedby comparison with the standard products and collected as describedabove.

1.2.5.

The composition of the TGS, CES, FFAS and PLS is determined by gas-phasechromatography of their methylesters. The methylesters are prepared bymethylation in known manner and are then extracted with hexane. Thepeaks of the compounds in the chromatograms obtained are identified bycomparison with the chromatograms of standard products.

1.3 Results

The results of analysis of the lipids are shown in Table 3 below:

                                      TABLE 3                                     __________________________________________________________________________                 TGS CES FFAS                                                                              CL  PI  PS  PC  PE                                   __________________________________________________________________________    Composition of the fatty acids in the lipid classes                           of the liver of guinea pigs fed on diet I (mol-%)                                 C18:2ω6                                                                          47.1                                                                              33.0                                                                              25.7                                                                              68.9                                                                              21.1                                                                              25.3                                                                              31.6                                                                              19.9                                     C18:3ω6 (GLA)                                                                    8.1 9.1 3.6 1.5 3.2 4.0 4.5 2.7                                  ω6                                                                          C20:3ω6 (DHLA)                                                                   2.3 7.0 1.4 2.1 7.5 3.6 2.7 2.3                                      C20:4ω6 (AA)                                                                     1.2 3.6 1.8 3.0 11.3                                                                              5.6 7.0 18.2                                     C18:3ω3                                                                          9.2 5.2 4.8 5.5 1.5 1.4 2.2 1.9                                      C18:4ω3                                                                          0.6 0.3 0.4 --  0.1 --  0.1 --                                   ω3                                                                          C20:5ω3 (EPA)                                                                    --  0.2 --  --  --  --  0.1 0.2                                      C22:5ω3                                                                          0.1 0.1 0.2 --  0.3 1.1 0.3 1.2                                      C22:6ω3                                                                          0.2 --  0.7 0.2 0.3 2.2 0.7 3.5                                      Ratio    1.9 1.9 0.9 0.7 0.7 0.7 0.4 0.1                                      C20:3ω6 (DHLA)                                                          C20:4ω6 (AA)                                                            Unsaturation                                                                           178 172 116 190 137 132 136 172                                      index                                                                     __________________________________________________________________________    Composition of the fatty acids in the lipid classes                           of the liver of guinea pigs fed on diet II (mol-%)                                C18:2ω6                                                                          53.8                                                                              47.2                                                                              23.7                                                                              69.4                                                                              25.1                                                                              34.0                                                                              41.3                                                                              27.0                                     C18:3ω6 (GLA)                                                                    0.6 0.4 0.7 --  --  0.1 --  0.4                                  ω6                                                                          C20:3ω6 (DHLA)                                                                   0.4 1.0 0.3 0.2 1.9 0.5 0.2 0.4                                      C20:4ω6 (AA)                                                                     0.8 2.3 2.0 2.5 14.8                                                                              4.7 4.6 14.4                                     C18:3ω3                                                                          9.1 6.5 4.5 4.0 1.0 1.5 2.2 1.8                                      C18:4ω3                                                                          --  --  0.1 --  --  --  --  --                                   ω3                                                                          C20:5ω3 (EPA)                                                                    --  --  --  --  0.1 --  --  0.1                                      C22:5ω3                                                                          0.3 --  0.1 0.2 0.3 0.7 0.3 1.2                                      C22:6ω3                                                                          0.2 --  0.9 0.6 0.4 1.8 0.9 4.5                                      Ratio    0.5 0.5 0.2 0.1 0.1 0.1 <0.1                                                                              <0.1                                     C20:3ω6 (DHLA)                                                          C20:4ω6 (AA)                                                            Unsaturation                                                                           162 150 96  179 133 121 126 167                                      index                                                                     __________________________________________________________________________    Composition of the fatty acids in the lipid classes                           of the liver of guinea pigs fed on diet III (mol-%)                               C18:2ω6                                                                          22.4                                                                              25.5                                                                              17.7                                                                              60.4                                                                              13.7                                                                              21.1                                                                              27.5                                                                              16.0                                     C18:3ω6 (GLA)                                                                    0.2 0.1 0.6 --  0.1 0.1 --  --                                   ω6                                                                          C20:3ω6 (DHLA)                                                                   0.2 0.2 0.2 0.2 2.8 0.8 0.4 0.3                                      C20:4ω6 (AA)                                                                     0.7 1.7 2.7 3.5 12.7                                                                              6.7 5.2 17.5                                     C18:3ω3                                                                          1.5 0.8 2.1 0.5 0.1 0.5 0.6 0.3                                      C18:4ω3                                                                          0.1 --  0.2 --  --  --  --  --                                   ω3                                                                          C20:5ω3 (EPA)                                                                    0.1 --  0.2 --  0.4 0.2 0.3 0.7                                      C22:5ω3                                                                          0.6 0.2 0.3  0.3                                                                              0.8 1.5 0.7 2.1                                      C22:6ω3                                                                          0.7 0.3 1.6 1.9 1.1 4.1 2.5 10.7                                     Ratio    0.3 0.1 0.2 0.1 0.3 0.1 0.1 <0.1                                     C20:3ω6 (DHLA)                                                          C20:4ω6 (AA)                                                            Unsaturation                                                                           104 104 91  170 124 129 119 196                                      index                                                                     __________________________________________________________________________

The above results show that the incorporation of GLA and DHLA isconsiderably greater in the case of the group fed on diet I containingHPC.

There is no significant difference between the three groups in regard tothe incorporation of AA. The result of these two observations is thatthe DHLA:AA ratio is considerably higher in the case of the ingestion ofHPC.

The incorporation of EPA is considerably greater in the case of theingestion of HPC than in the case of the ingestion of WO in regard tothe TGS, CES, PCS and PES. The same observation is true for theingestion of L in regard to the TGS and CES.

The unsaturation index shows that guinea pigs are capable of largelycompensating the difference in unsaturation of the fatty acids of thediets.

In short, the above results show that the ingestion of HPC results inthe substantial incorporation of DHLA and in higher DHLA/AA ratios inall the classes of hepatic lipids. In addition, the incorporation of EPAis greater for the regime based on HPC than for the regime based on WO.It follows from this that the potential of the PG1S and PG3S bycomparison with the PG2S is clearly demonstrated in regard to HPC.

EXAMPLE 2 Influence of the Ingestion of HPC on the Fatty AcidComposition of the Plasma Lipids in Human Beings

A metabolic study is conducted on a 32-year-old man in good health towhom capsules of HPC concentrate enriched with GLA (78%) and SA (16%)are administered for 6 weeks in accordance with the following schedule:

    ______________________________________                                        Days 1-20: 3 capsules/day, corresponding to approxi-                                     mately 1 g GLA and 250 mg SA/day                                   Days 21-26:                                                                              10 capsules/day corresponding to approxi-                                     mately 3 g GLA and 0.8 g SA/day                                    Days 27-37:                                                                              administration interrupted because of                                         influenza                                                          Days 38-42:                                                                              10 capsules/day, corresponding to approx. 3                                   g GLA and 0.8 g SA/day                                             ______________________________________                                    

Analysis of the fatty acids of the various classes of blood serum lipidsis carried out by gas chromatography of the methylesters in comparisonwith the control consisting of the mean of a group receiving a placebo.

The results are shown in Table 4 below.

                                      TABLE 4                                     __________________________________________________________________________    Fatty acid composition of the various classes of serum lipids in mol-% of     the HPC                                                                       concentrate and the control                                                            PLS         FFAS        TGS         CES                                       HPC         HPC         HPC         HPC                              Fatty acids                                                                            Concentrate                                                                          Control                                                                            Concentrate                                                                          Control                                                                            Concentrate                                                                          Control                                                                            Concentrate                                                                          Control                   __________________________________________________________________________    C20:3ω6 (DHLA)                                                                   8.35   3.83 0.93   0.48 1.60   0.38 1.97   0.88                      C20:4ω6 (AA)                                                                     16.30  14.92                                                                              1.61   1.29 3.12   1.49 11.75  9.68                      C20:3ω6                                                                          0.51   0.26 0.58   0.02 0.51   0.25 0.17   0.09                      C20:4ω6                                                                 C20:5ω3 (EPA)                                                                    0.94   0.68 --     --   0.58   0.27 0.91   0.65                      C22:5ω3                                                                          1.52   1.28 0.87   0.19 0.90   0.50 0.18   --                        C22:6ω3                                                                          2.52   2.76 0.57   0.15 0.36   0.19 0.45   0.43                      __________________________________________________________________________

Evaluation of the above results shows that the GLA ingested isincorporated in all the classes of serum lipids and is rapidlymetabolized into DHLA and, to a lesser extent, into AA. An increase isobserved in the long-chain ω3 fatty acids, particularly EPA, in relationto the control, which seems to suggest that SA is also incorporated.

It may be concluded that the synthesis potential of the PG1S and PG3S ishigh by comparison with the PG2S when the regime is supplemented withHPC.

EXAMPLE 3 Thrombosis and Adhesion of Blood Platelets

3.1

Study of the incorporation of fatty acids in the arterial walls.

In this Example, guinea pigs are fed on diets containing various lipidsover a period of 6 weeks, after which the fatty acid composition of theaortas of the animals is determined. The composition of the principalfatty acids of the lipids of the diets is shown in Table 5 and that ofthe fatty acids of the aortas in Table 6 below.

                  TABLE 5                                                         ______________________________________                                        Composition of the principal fatty acids (in mol-%) in the                    diets containing the lipids                                                             HPC  WO          L      FO                                          ______________________________________                                        C14:0       0.1    0.1         1.8  3.0                                       C16:0       7.0    7.8         26.4 24.9                                      C16:1       0.1    0.1         2.1  3.3                                       C18:0       1.4    2.1         15.4 12.8                                      C18:1ω9                                                                             11.3   17.3        37.3 34.8                                      C18:2ω6                                                                             46.0   58.5        15.4 11.9                                      C18:3ω6                                                                             16.8   --          --   0.1                                       C18:3ω3                                                                             14.3   13.9        1.1  2.0                                       C18:4ω3                                                                             3.0    --          0.2  0.4                                       C20:5ω3                                                                             --     --          0.1  1.7                                       C22:6ω3                                                                             --     --          0.2  3.2                                       Total ω6's                                                                          63.0   58.5        12.6 12.7                                      Total ω3's                                                                          17.3   13.8        1.8  7.3                                       ω6:ω3 ratio                                                                   3.6    4.2         8.7  1.8                                       ______________________________________                                         Legend:                                                                       FO = oil containing 20% fish oil, 70% lard and 10% walnut oil                 L = lipid containing 90% lard and 10% grapeseed oil                      

                  TABLE 6                                                         ______________________________________                                        Composition of the principal fatty acids (in mol-%) of the                    aortas of guinea pigs fed on the diets containing the                         lipids                                                                                   HPC    WO       L        FO                                        ______________________________________                                        C18:1ω9                                                                              20.46    27.60    43.19  41.76                                   C18:2ω6                                                                              30.58    32.95    6.51   5.97                                    C18:3ω6                                                                              4.47     0.33     0.12   0.03                                    C18:3ω3                                                                              6.07     4.10     0.71   0.64                                    C20:3ω6 (DHLA)                                                                       1.43     0.13     0.10   0.05                                    C20:4ω6                                                                              0.97     0.62     0.91   0.91                                    C20:5ω3                                                                              --       --       --     0.01                                    ______________________________________                                    

A substantial increase is observed in the level of DHLA where HPC isingested. This means that the formation potential of the PG1S isincreased in the blood vessels.

3.2

Study of the influence of diet on the biological functions of the bloodplatelets.

The capacity of the blood platelets of guinea pigs marked with [³H]-adenine to adhere to a thrombogenic surface in the form of discscoated with fibronectin is measured after 4 weeks on the diets ofExample 3, Table 5. The number of platelets which have adhered to thediscs is counted. The results are shown in Table 7 below.

                  TABLE 7                                                         ______________________________________                                                      Diet containing the lipids                                                    HPC   WO       L      FO                                        ______________________________________                                        Number of platelets                                                                           1.9     2.3      4.0  2.3                                     which have adhered to                                                         the discs/cm.sup.2 × 10.sup.5                                           ______________________________________                                    

Where HPC is ingested, there is a reduction in adhesion compared withall the other diets, including that containing fish oil.

3.3.

Study of the thrombogenicity of the vessel wall and adhesion of theplatelets,

To study the influence of the fatty acids of the regime on thethrombogenicity of the blood vessels, groups of rabbits are fed with thesemi-synthetic diets HPC, WO and FO (Table 5, Example 3) and acommercial diet ("chow", C). After 4 weeks of the regime, a lesion ismade in the carotid artery of the rabbits fed with HPC, WO and FO. Therabbits are then injected with blood platelets marked with [hu3H]-adenine from donor rabbits fed on diet C. "In vivo" measurement ofthe accumulation of the platelets on the wounded artery tests thereactivity of the blood vessel. To discriminate the effect of the regimeon the reactivity of the platelets from its effect on the reactivity ofthe blood vessel, platelets are isolated from the blood of rabbits fedon the 4 diets and their adhesion to discs coated with fibronectin ismeasured "ex vivo".

The capacity of the blood vessels to synthesize 13-HODE and the capacityof the platelets to synthesize 12-HETE is also determined.

The results are shown in Tables 8 and 9 below.

                  TABLE 8                                                         ______________________________________                                        Number of platelets                                                                        Diet containing the                                                                           Commercial                                       which have adhered to                                                                      lipids          diet                                             the discs/cm.sup.2 × 10.sup.5                                                        HPC     WO      FO    C                                          ______________________________________                                        In vivo      36      52      48    69                                         Ex vivo      15      18       9    50                                         ______________________________________                                    

It can be seen that the thrombogenicity of the blood vessel "in vivo" islower with the HPC regime and that there is no difference between the WOand FO regimes. The "ex vivo" measurements of the adhesion of theplatelets show a reduced platelet reactivity with the HPC,WO and FOregimes compared with the C regime.

                  TABLE 9                                                         ______________________________________                                                   Diet containing the                                                                         Commercial                                                      lipids        diet                                                            HPC   WO      FO      C                                            ______________________________________                                        Metabolites of                                                                             30.2    27.0    4.9   12.6                                       the lipoxygenase                                                              13-HODE (ng/cm.sup.2                                                          of vessel)                                                                    12-HETE (ng/cm.sup.2                                                                        2.7     2.4    1.2    9.3                                       platelets)                                                                    ______________________________________                                         Legend:                                                                       ng = nanogram                                                            

No difference is observed in the synthesis of 12-HETE by the plateletsof the animals fed on the HPC, WO and FO diets. By contrast, thesynthesis of 13-HODE by the vessels is greater with the HPC and WOregimes which is consistent with the higher content of linoleic acid inthe blood vessels of these two groups and with the anti-adhesive effectof 13-HODE.

EXAMPLE 4 Metastases

4.1

To study the influence of diet on the proliferation and dissemination ofmetastases, rats are fed on the diets of Example 3, Table 5, except forthat containing WO, over a period of 5 weeks.

One group of rats is fed on a standard so-called "chow" diet (C). Tumourcells (Walker 256) are cultured in a medium containing the radioactivenucleotide [¹²⁵ I]-uridine marking the tumour cells. The rats are theninjected with the cells. The animals are killed 24 hours later and theradioactivity incorporated in the lungs is determined.

The results are shown in Table 10 below.

                  TABLE 10                                                        ______________________________________                                                   Diet containing the                                                                         Commercial                                                      lipids        diet                                                            HPC   L       FO      C                                            ______________________________________                                        Number of tumour                                                                           3.6     13.1    1.0   8.5                                        cells × 10.sup.4                                                        ______________________________________                                    

It can be seen that HPC and FO produce the lowest incorporation oftumour cells. It may be assumed that this effect is attributable to aninteraction between the tumour cells and the endothelial cells of theinner walls of the blood vessels: there is less inter-cell adhesion.

4.2

A study is conducted in guinea pigs on the basis of the test of Example3.2, but applied to animals injected beforehand with tumour cells.

The animals are injected with the tumour cells after 4 weeks' ingestionof the diets and are kept on the diets for another three weeks. Thecapacity of the blood vessels to synthesize 13-HODE is measured byincubating them with LA. The adhesion of the platelets to the discs isdetermined as in Example 3.2. The number of animals with lesions of thelungs and the number of lesions per lung are also determined. Theresults are shown in Table 11 below.

                  TABLE 11                                                        ______________________________________                                                      Diet containing the lipids                                                    HPC    WO      L       FO                                       ______________________________________                                        Number of platelets which                                                                     3.6      6.6     7.1   4.1                                    have adhered to the discs/                                                    cm.sup.2 × 10.sup.5                                                     % of lungs with 33       40      55    33                                     lesions/total                                                                 Number of lesions                                                                             8.9      9.8     21    22                                     per lung                                                                      Mol-% of 13-HODE in the                                                                       9.4      8.6     5.5   2.9                                    inner wall of the blood                                                       vessels                                                                       ______________________________________                                    

It can be seen that, as in the case of the normal animals (Example 3.2),the ingestion of HPC, like that of FO, results in a reduction in theadhesion of the platelets in the animals injected with tumour cells. Thenumber of lungs bearing lesions is lowest for HPC and FO although thenumber of lesions per lung is distinctly lower for HPC.

However, a histological study has shown that the lesions were ofinflammatory origin and non-cancerous. Accordingly, there is lessinflammation with HPC.

The analysis results for 13-HODE show an increased presence of thisanti-adhesion mediator when the animals are fed with HPC.

EXAMPLE 5 Inflammation

The polynuclear leucocytes (PMNS) play a decisive part in theinflammatory process and, to that end, they have to leave the bloodvessels to enter the peripheral tissues. One of the steps leading tothis process is their preliminary adhesion to the inner wall of theblood vessels.

This adhesion is observed by studying the attraction between the PNMSisolated from guinea pigs fed on the diets of Example 3, Table 5 andmonolayers of endothelial cells on the discs. The results are shown inTable 12 below.

                  TABLE 12                                                        ______________________________________                                                      Diet containing the lipids                                                    HPC    WO      L       FO                                       ______________________________________                                        Number of PMNS per disc                                                                       1391     1938    1310  2193                                   ______________________________________                                    

It can be seen that the ingestion of HPC results in a weak attraction ofthe PMNS to the endothelial cells.

We claim:
 1. A method for treating cancer metastases comprisingadministering lipids obtained from seeds of blackcurrant to a human inan amount effective for reducing inter-cell adhesivity of cells forreducing cancer metastases.
 2. A method according to claim 1 wherein thelipids are administered in a daily dose of from 1 g to 25 g.
 3. A methodaccording to claim 1 wherein the lipids are administered in a form ofblackcurrant seed oil in a daily dose of from 2 g to 5 g of the oil. 4.A method according to claim 1 wherein the lipids are administered in aform for oral administration.
 5. A method according to claim 4 whereinthe lipids are in a form for enteral or parenteral administration.
 6. Amethod according to claim 1 wherein the lipids are administered in aform for rectal administration.
 7. A method according to claim 1 whereinthe lipids are administered in a form of a dietetic composition.